Motorcycle Assembly; Rectification; Bonding - ZONGSHEN ZS250GY-3 Service Manual

Please refer to the specialized list or the following formula for the bit diameter of bottom hole :
Diameter of drilling hole outside diameter of screw thread - 1.1mm×screw pitch(appropriate for iron
and copper)
Diameter of drilling hole outside diameter of screw thread-1.2mm×screw pitch(appropriate for steel
and brass)
When cutting inside threads,turn master tap into the chamfer-angle hole,then take out and use plug tap
to shape the threads.
The tool for outside screw threads cutting is screw plate.Screw plate includes fixed screw
plate,adjustable screw plate and active screw plate.Usually,we use fixed screw plate,i.e.round screw plate.
When cutting outside screw threads,choose screw plate and diameter of club-shaped material according
the required material,diameter of screw thread and screw pitch.To make proper choice,please refer to the
specialized list or the following formula:
Diameter of club shaped materialoutside diameter of screw thread-0.13mm×screw pitch
Bevel the end of club-shaped material in 15°～20°angle before cutting outside screw threads.
To ensure easy operation,the screw plate and club-shaped material should be in vertical,therefore,the
minimum diameter of cone angle should less than inside diameter of screw thread.

[6]Rectification

The operation that eliminates the unevenness of plane-shaped,bar-shaped and column-shaped parts is
called rectification.。Rectification can reshape the parts.
The rectification depends on the flexibility of metal parts.Therefore,metal parts with good flexibility can
be rectified directly,such as soft steel and red cooper'metal parts with less flexibility need to anneal before
rectification.
The ways for rectification are torsion,extension,bending and expansion.

[7]Bonding

Bonding is widely used in manufacture and repairs because it operates easily and can be done without
special equipment and expensive materials. In addition,the bonding parts don't need to be processed by
high precision machine,such as the bonding of handlebar and steering head,bonding of plastic label and
spay-paint metal parts,bonding of brake disc and brake pads.There are various adhesive,such as epoxy
adhesive,phenol formaldehyde adhesive and so on.
（5）Motorcycle assembly
The last procedure in repair is assembly,which is a key to ensure the good quality of motorcycle.
[1]Assembly includes module assembly,parts assembly and overall assembly.In the process of
assembly,we should abide by the principle that assemble module first,then parts and the overall finally.
The sequence of assembly is opposite to disassembly,which is to first assemble the last disassembled
components,and to last assemble the first disassembled components.
[2]Module assembly is the first stage in whole process,which makes the parts into a single module,such
as the combination of front brake drum cover,the combination of brake pads ,the combination of wheel.
[3]Parts assembly is based upon module assembly,which assembles the parts and module as a
whole,such as front and rear wheel assembly,front fork assembly,shock absorber assembly and so on.
[4]Overall assembly is the last procedure to complete the whole working process,which connects parts
and modules with frame according to installation sequence by all means.
[5]The sequences of overall assembly are similar.The operation is as following：Firstly,finish all
modules assembly and parts assembly,then install engine assembly and gearbox assembly on frame.
Secondly,install front fork assembly,handlebar assembly,front and rear fender assembly,shock absorber
assembly,carrier assembly,front and rear wheel assembly,fuel tank assembly and seat assembly.
Thirdly,install headlight,taillight,steering indicator,horn and battery assembly.The fourth,connect all electric
circuit and control cables.The fifth,install driving chain, dentiform belt,wind shield and chain cover or belt
cover.Last,lubricate the whole motorcycle.
[6]Consult the following reference about disassembly,installation and inspection if there is any
assembly sequence difference which is caused by different type and structure.
[7]Pay attention to the following:：
Choose a clean and wide place ；strictly follow the assembly requirements；parts connecting should
accord with specification ;avoid misfitting and leaving out of any gaskets,cotter pin and fixing clip.
3 Adjustment after Repair
The interconnection of parts have been affected in some extent after repair.To recover the performance
of motorcycle,adjust them according to the specification of user'smanual.adjust as follows:
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